1. Field of the Invention
The present invention relates to a bearing device having a rolling bearing fitted on a shaft. This bearing device can be utilized, for example, in the fields of a vehicular hub unit or a guide roller of the slide door of an automobile, and in other general fields of bearing devices.
2. Description of the Related Art
With reference to FIG. 17, a vehicular hub unit will be described as one example of the bearing device. In this hub unit B, a double row angular contact ball bearing 82 with vertex of contact angles outside of bearing is fitted on a journal 81 of a hub wheel 80. The free end of the journal 81 is rolled-caulked to bend radially outward. This bent caulked portion 85 is pushed onto the outer end face of an inner ring 84 of the bearing 82. As a result, the bearing 82 is so fixed on the hub wheel 80 as to be prevented from coming out.
The caulked portion 85 is so curved as to have an entirely roundish outer end face, as shown in FIG. 18. The curve at the outer end face of the caulked portion 85 has a single radius of curvature r0.
The cylindrical free end of the journal 81 at the hub wheel 80 is rolled-caulked by using a caulking jig 90, as shown in FIG. 19. At this time, the leading end of the caulking jig 90 is applied to the journal 81 and is rolled at a predetermined angle θ on a single-dotted line O. As a result, the free end of the journal 81 is bent radially outward so that the inner ring 84 is prevented from coming out by the bent caulked portion 85.
In the example of the prior art thus far described, the shape of the outer end face of the caulked portion 85 is not strictly managed. This outer end face of the caulked portion 85 usually has a roundish shape. As a result, the shape of the caulked portion 85 may disperse for the caulking works. In an extreme case, the radially intermediate portion of the caulked portion 85 may leave and float over the inner ring 84. In this case, a resistance to a coming-out load, i.e., a coming-out resistance has a tendency to fall short.
On the other hand, the outer end face of the caulked portion 85 may be formed of a curve having a single radius of curvature r0. The caulked portion 85 of this outer end face shape is achieved by a caulking treatment under a substantially constant pressure from the initial to final stages of the caulking process. In this case, too, there occurs the aforementioned defect.
Against this defect, it is conceivable to inspect the finished state of the caulked portion 85 visually after the caulking treatment. Since the outer end face of the caulked portion 85 has the roundish shape, however, it is impossible to confirm from the appearance whether or not the floating state has occurred.